Latch bolt hold-back



Aug. 29, 1961 F. .1. RUSSELL LATCH sour HOLD-BACK 3 Sheets-Sheet 1 Filed Sept. 14, 1959 FRED J RUSSELL A TTORNE Y5.

Aug. 29, 1961 Filed Sept. 14, 1959 F. J. RUSSELL LATCH BOLT HOLD-BACK 3 Sheets-Sheet 2 q Q 9 E2 FRED J RUSSELL INVENTOR.

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ATTORNEYS Aug. 29, 1961 F. J. RUSSELL LATCH BOLT HOLD-BACK 3 Sheets-Sheet 3 Filed Sept. 14, 1959 FRED J RUSSELL ATTORNEYS United States Pate 2,998,274 LATCH BOLT HOLD-BACK Fred J. Russeil, 3800 Don Felipe Drive,

Los Angeles 8, Calif. V Filed Sept. 14, 1959, Ser. No. 839,765 '6 Claims. (Cl. 292-169) The invention relates to door locks and is especially directed to a door lock which finds special use in places like entrance doors to public premises such as stores, oflice buildings and other establishments where the door may be opened and closed a great many times during the days business. The invention is directed particularly to a lock which can be so manipulated that the latch bolt can be locked in retracted position, removed entirely from aprotruding adjustment, and therefore inoperable in that adjustment so that the door can be easily swung opened and closed.

It is quite commonly appreciated that doors for public places which need to be swung frequently should not have a latch bolt which protrudes. Many doors of this type have a latch bolt which can only be extended by a key when the door is to be locked. This has certain disadvantages in that there may be occasions when it is desirable to have the door latch shut without having it in locked position so that it cannot inadvertently swing open. With doors equipped only with the latch bolt which only can be extended by a key, there is no easy way to keep the door closed, for example, against the force of wind or something similar and still be openable without use of a key. n those devices which have attempted to provide a hold-back for the latch bolt, mechanisms available have often been accessory mechanisms, outside of the lock mechanisms, which have been unnec- 'essarily complicated, expensive to construct and bothersome to install and operate. Extra mechanisms outside of the lock itself also tend to detract from the clean swept installation on certain modern types of doors.

It is therefore among the objects of the invention to provide a new and improved door lock wherein a holdback mechanism for the latch bolt is incorporated within the lock structure itself in a new and improved manner such that it can be easily set in adjustment by normal keying or turn button means.

Another object of the invention is to provide a new 'and improved door lock incorporating a hold-back feature for the latch bolt which by a simple rapid adjustment at the same time is capable of barring both the inside and outside knob against rotation, thus converting them to rigid push-pull handholds.

Still further among the objects of the invention is to provide a new and improved door lock incorporating a latch bolt hold-back feature which is so constructed that the hold-back and barring of both knobs is manipulated entirely by use of a conventional key extended through one of the knobs, preferably the inside knob or by use of a conventional turn button located in one of the knobs.

Also among the objects of the invention is to provide a comprehensive look mechanism featuring the latch bolt hold-back feature as described above, together with conventional locking and unlocking adjustment, so that the lock may be also employed as a normal door lock when it is desired to latch or to lock'the door in closed position.

Patented Aug. 29, 1961 accompanying drawings.

In the drawings: FIGURE 1 is a transverse sectional view of the doc lock showing the adjustment prevailing when the latch bolt is in hold back position.

FIGURE 2 is an exploded view of the mechanism lyin within the inner knob spindle.

FIGURE 3 is a perspective view of the inner knob spindle.

FIGURE 4 is a fragmentary elevational view of the roll back end of the inner spindle showing the dogging member in latch hold-back position.

FIGURE 5 is a transverse sectional view similar to FIGURE 1 showing the adjustment prevailing when the latch bolt is extended and the lock is unlocked.

FIGURE 6 is an exploded view of the mechanism lying, within the outer knob spindle.

FIGURE 7 is a perspective view of the outer knob spindle.

FIGURE 8 is a cross-sectional view taken on the line 8-8 of FIGURE 1.

FIGURE 9 is a cross-sectional view taken on the line 9--9 of FIGURE 1.

FIGURE 10 is a cross-sectional view taken on the line Iii-10 of FIGURE 5.

FIGURE 11 is a cross-sectional view taken on line 11--11 of FIGURE 5.

FIGURE 12 is a transverse sectional view similar to FIGURE 1 showing the adjustment prevailing when the latch bolt is extended and the lock is locked.

In an embodiment of the invention chosen for the purpose of illustration there is shown mounted in a door 10 a door lock consisting of an outside knob assembly 11; an inside knob assembly 12, a latch bolt assembly 13 having a latch bolt 14 extending therefrom, and a stationary portion consisting of a frame 15 having a housing 16 extending therearound and containing a retractor indicated generally by the reference character 17.

Extending outwardly from the frame 15 is a spindle bearing 18 around which is a retaining collar 19 and escutcheon 20. Similarly on the opposite side of the frame is a spindle bearing 21 having a retaining collar 22 therearound retaining an escutcheon 23.

The outside knob assembly 11 consists essentially of an exterior portion terminating in a knob face plate 26 and a sleeve 27 which slides over an outside knob spindle 28, the outer end of which contains an outside locking cylinder 29. The knob assembly is fastened to theoutside knob spindle by employment of apin 30 which prevents -the knob from being removed and from rotating relative to the spindle. It will be noted that a roll back 31 (see FIGURE 5) onthe-outside knob spindle'28 is positioned to engagewith a shoulder 32 .of the retractor 17-so that by rotation of the outsideknob spindle the retractor can be withdrawn. The retractor in turn has projections 33 thereon (see FIGURE 5) in engagement with a tail piece 34 of the latch bolt 14 so that motion of the retractor is communicated to the latch bolt, thereby to withdraw the latch bolt. Springs 35 bearing outwardly against a spring keeper 35 (see FIGURE A re in the housing 16 and inwardly against the retractor tends normally to urge the retractor in a direction extending the latch bolt 14 except when withdrawn by action of the roll back.

Located inside of the outside knob spindle 28 is a retractor spindle 36. This spindle is also provided with a roll back 37 (see FIGURE 6) which is positioned to move against one of the shoulders 32 on the retractor so that the retractor can be moved from the outside of the door either by the knob assembly 11 or the retractor spindle 36 which incidentally is manipulated by the locking cylinder 29 and a key 38. To accomplish this, a tail piece 39 connected to the locking cylinder by conventional means extends into a rectangular slot 40 in a bottom 41 of the retractor spindle 36 so that when the key rotates the interior of the locking cylinder in a conventional fashion, the retractor spindle is rotated.

Located inside of the retractor spindle 36 is a dogging assembly consisting of a body 42, a dogging member 43, and a washer 44. The dogging member is keyed nonrotatably upon the body 42 by some conventional means as, for example, splines 45. An extension 46 on the dogging member always is engaged within a recess 47 (see FIGURE in the stationary portion of the lock at the junction of the frame with the outside knob spindle bearing 18.

The washer 44 is rotatably attached but axially retained on the body 42 by the spring 51 but particularly by the end loop 51 which bears against the projection 48 of washer 44, thus urging the washer 44 into engagement with the groove 42' of the body 42. The tabs 49, 49', fall into appropriate slots 50, 50' of the retractor spindle 36 to permit the dogging member 43 to shift axially within the retractor spindle 36 by virtue of the length of the slots 50, 50'. dogging member and particularly the washer 44 and at the other end against the bottom 41 of the retractor spindle 36 tends normally to urge the dogging member toward the left, as viewed in FIGURE 5. This means that the dogging member tends normally to be springpressed out of a position barring rotation of the outside knob spindle 28 and the outside knob assembly 11.

A spring 52 bottomed upon a spring keeper 53 which in turn is contained by the outside spindle is employed to extend the pin 30 and to permit depression of the pin 30 when the knob assembly 11 is to be removed.

The operating structure on the inside knob side of the lock is somewhat different from that hereinabove described for the outside area except for the provision of an inside locking cylinder 56 operated by a key 57 which causes a tail piece 58 to rotate when the parts are to be manipulated by the key. In this instance also, a pin 59 under impetus of a spring 60 contained by a keeper 61 extends outwardly from the inside spindle 62 into the inside knob assembly 12, thereby to releasably contain the inside knob assembly on the inside knob spindle 62. The inside knob assembly has a knob face plate 63 which serves a purpose similar to the knob face plate 26 on the outside knob assembly 11.

Within the inside knob spindle 62 is a cam sleeve 64 which has a bottom 65 provided with an opening 66 into which the tail piece 58 fits so that upon rotation of the key 57, the cam sleeve 64 can be rotated.

Within the cam sleeve 64 is a dogging member indicated generally by the reference character 67. The dogging member has a dogging element 68 thereon, having an extension 69 which at all times extends through a recess 71 within the spindle bearing 21 which is a portion of the frame 15 and which is a stationary part of the lock. The recess 71 is elongated and permits the dogging memher and extension to move in an axial direction.

When the extension 69 is located in the stationary recess 71 and at the same time is located in the slot 75 of inside spindle 62, the inside knob assembly cannot turn.

When the extension 69 is located in the stationary re- A spring 51 hearing at one end against the 7 cess 71 and at the same time is located in the arcuate recess 70 of inside spindle 62, the inside knob spindle 62 nevertheless is permitted to rotate a distance equal approximately to the length of the arcuate recess 70 so that roll backs 72, 72 can move against appropriate shoulders 73 of the retractor, thereby to reciprocate the retractor and accordingly withdraw the latch bolt 14. It should further be noted, however, that when the inside knob spindle 62 is rotated to a position wherein the extension 69 is urged to a position within either the enlargement 74 or 74 of the arcuate recess 70 (FIGURE 4), the inside knob spindle 62 is rendered incapable of rotation and the latch bolt 14 is held in retracted position as shown in FIGURE 1.

From the foregoing brief description, it will be clear that the dogging member 67 is subject to endwise adjustment. This is acomplished by operation of a hold back operator in company with a spring 85. The holdback operator has a transverse bore 81 therein within which is positioned a cam pin 82. The cam pin in turn extends through openings 76, 76' in the dogging member and through cam slots 83, 83' at the respective opposite ends, these cam slots being obliquely positioned in the wall of the cam sleeve 64. Dead end recesses 84 (see FIGURE 2) and 84' (not shown), respectively, provide a temporary retaining means for the camming pin 82 when it reaches that end of its operation. The pin 82 extends outwardly into slots 92 (see FIGURE 3) and 92' (not shown) in the inside knob spindle 62.

The spring 85 seats at one end around a keeper 86 on the hold-back operator 80 and at the other end bears against a shoulder 87 located within the dogging member 67.

A snap ring 88 is positioned against an end 89 of the cam sleeve 64, and a projection 90 on the snap ring 88 fits within a slot 91' (see FIGURE 4) on the inside spindle 62; similarly, and diametrically opposed to projection 90, projections 90, 90" extend into the arcuate slot 91 of the inside spindle 62. Snap ring 88 and pin 59 retain the cam sleeve 64 axially Within inside knob spindle 62.

Consequently, when the cam sleeve 64 is rotated by operation of the key 57, it will cause the cam slots 83, 83 to move against the cam pin 82 and since this is confined within the hold-back operator 80, the hold-back operator will be moved axially, depending on the direction of rotation of the cam sleeve 64. When the pin is in the position illustrated in FIGURE 1, the spring 85 extends the dogging member 67 toward the right. When the cam sleeve is rotated to shift the pin 82 to the opposite end of the cam slot 83, 83, tension is relieved in the spring 85. At the same time the pin engages shoulders 77, 77' at ends of the opening 76, 76' respectively and draws the dogging member toward the left, as shown in FIGURE 5 and FIGURE 12.

An important element in the mechanism resides in a hold-back rod 95. This rod extends in an axial direction through the retractor. A reduced end element 96 of the hold-back rod provides a shoulder 97, the reduced end element 96 being received within a bore 98 in the body 42 and the shoulder 97 being in a position bearing against an inner end wall 99 and the dogging element 43 which is non-rotatably attached to the body 42. A longer reduced end element 100 at the opposite end of holdback rod provides a shoulder 101. The end element extends through a bore 102 in the dogging member 67 and continues into a position of engagement with the end of the spring keeper 86 of the holdback operator 80. It will be clear from this that axial movement of the hold-back operator 88 is capable of causing a shift of the hold-back rod 95 in an endwise direction from left to right as viewed in FIGURE 1 from the position as viewed in FIGURE 5.

Before the mechanism has been operated to place the latch bolt 14 in hold-back position, as illustrated in FIG- URE 1, let it be assumed that the lock parts have the adjustment illustrated in FIGURE 5. In this position it Will be understood that the inside knob spindle 62 has a position of rotation such that the channel 70 lies opposite the extension 69 of the dogging element 68. In this position of adjustment also, the extension 46 of the dogging member 43 is within the recess 47, and in alignment with but outside of the open end slot 103 in the outside knob spindle 28. In these various positions the outside knob assembly 11 can be rotated, thereby to rotate the outside knob spindle 28 to manipulate the roll back 31 and hence the latch bolt. On the Opposite or inner side, the inside knob assembly 12 can be rotated in either direction so that either of the roll backs 72, 72' can be moved against the retractor to withdraw the latch bolt 14.

When it is desired to bar rotation of the outside knob assembly 11 but permit the latch bolt to be withdrawn only by use of the outside key 38, the inside key 57 is rotated about one-quarter of a revolution in a counterclockwise direction as viewed from a position facing the knob. This motion causes rotation of the cam sleeve 64 in the same counterclockwise direction and shifts the cam pin 82 from the ends of the cam slots 83, 83' to the opposite end where dead ends 84, 84 are located. This allows the dogging member 67 to move from left to right, as shown in FIGURE 12, thus allowing the spring 85 to urge the extension 69 of the dogging element 68 to move out of arcuate recess 70 and into locking recess 75. The latch bolt, however, remains for this adjustment in the extended position of FIGURE 12. However, the hold-back pin 95 at the same time is shifted to the position of FIGURE 12, and this moves the dogging member 43 into the locking recess 47 and endwise or axially within the open end slot 103 of the outside knob spindle 28. Hence, the outside spindle is barred against rotation by fixing the position of the dogging member 43 as just described. By reason of the fact that a recess 104 in the retractor spindle 36 has an arcuate length of about onequarter turn, the retractor spindle 36 remains free for rotation by manipulation of the outside key 38 in one direction a distance sufficient to shift the retractor and Withdraw the latch bolt 14 by use of the key at the outside knob assembly.

When it is desired to lock the latch bolt 14 in withdrawn position and to bar both the outside knob assembly and the inside knob assembly against rotation, a different adjustment is necessary. This adjustment constitutes first rotating the inside knob assembly 12 either in a clockwise; or in a counterclockwise direction as viewed from a position facing the knob a distance sufficient to withdraw the latch bolt to the position shown in FIGURE 1. Rotation of the inside knob assembly as described causes a corresponding rotation of the inside spindle 62 a distance sufiicient to place the enlargement 74 or 74' opposite the extension 69. After the inside knob assembly 12 has been rotated in a counterclockwise direction, the inside key 57 is then rotated in a counterclockwise direction about one-quarter turn, causing the cam sleeve 64 to be rotated counterclockwise a corresponding distance suflicient to shift the cam pin 82 along the cam slots 83, 83' from the position shown in FIGURE to the Position shown in FIGURE 1. When the cam pin 82 is moved as described, the hold-back operator 80 is moved against the spring 85 and at the same time the dogging member 67 and dogging element 68 are allowed to move in a direction from left to right, as viewed in FIGURE 1 and FIGURE 4-. This moves the extension 69 out of arcuate slot 70 and into enlargement 7 4, as shown in FIGURE 4, which is no wider than said extension. This engagement of extension 69 with enlargement 74' holds the inside spindle 62 in rotated position, thus holding the latch bolt 14 in retracted position. Also, this has the same efifect upon the hold-back rod 95 as has previously been described, narnely, in causing the boldback rod to push the dogging member 43 and extension 46 thereon to a. position within the recess 47. This bars rotation of the outside knob assembly 11 in the same manner as has already been taught.

By reason of the fact that the extension 69 is thus confined within the enlargement 74, the spindle 62 is "barred from rotation. Because of the fact that this ad .justment occurs when the roll back 72 is in engagement with the retractor 17 in an adjustment holding the latch bolt 14 in the Withdrawn position of FIGURE 1, the latch bolt remains withdrawn. Accordingly, the door is free to be opened from either side by pulling upon the inside knob assembly 12 without rotating it or by pushing upon the outside knob assembly 11 without rotation. It will be appreciated in this connection that the adjustment just described is usable in conjunction with a latch bolt of the unbeveled type should the mechanism be made use of in a swinging type door which can swing either in or out.

To return the parts from the position shown in FIG- URE 1 to the position shown in FIGURE 5, it is necessary only to rotate the inside key 57 about one-quarter turn clockwise. This by rotation of the cam sleeve 64 returns the cam pin 82 to the ends of the slots 83, 83', as shown in FIGURE 5. At the same time the spring 51 pushes the body 42 of the outside dogging member to- Ward the left, as viewed in FIGURE 5, so that the extension 46 of the dogging member 43 is disengaged from the open end slot 103 in the outside knob spindle 28. Hence, the outside knob assembly is again free to be manipulated to retract the extended latch bolt 14. Concurrently, the inside knob spindle 62 is released by the shifting of the extension 69 out of the enlargement 74' into the arcuate recess 70, in which position the springs 35 bearing against the retractor 17 moves the retractor back to initial position, permitting the latch bolt 14 to extend outwardly again to the position shown in FIGURE 5.

Whereas the embodiment of the invention above described shows an inside locking cylinder 56 operated by a key 57 in the inside knob assembly 12, it should be recognized readily that a turn button mechanism might be substituted in place of this locking cylinder 56.

Whereas the embodiment of the invention above described shows the inside knob assembly 12 to be nonrotatable when the lock is adjusted as shown in FIGURES 1 and 12 by reason of the cutouts 74, 75 and 74 in the inside spindle 62, it should be easy for anyone skilled in the art of metal working to recognize that cutting from one end of arcuate slot 70 from left to right will eliminate one of the enlargements 74, 74' entirely and will widen the locking recess 75 sufficiently to allow the inside knob assembly 12 to rotate in one direction and thus always be able to retract the latch bolt, even when the lockis adjusted as shown in FIGURE 12. I

While the invention has herein been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is' not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described the invention, what is claimed as new in support of Letters Patent is: i

1. In a door lock a frame, a first spindle bearing and a second spindle bearing comprising a stationary portion, a reciprocating latch bolt, a retractor reciprocatably mounted in the frame and operatively connected to the latch bolt, a first spindle having a knob attached thereto and mounted in said first spindle bearing and a second spindle having a knob attached thereto and mounted in said second spindle bearing, at least one of said spindlesv being a rotatable spindle and having a roll-back meansv .nonrotatabl'e engagement with the stationary portion and,

one spindle is blocked against rotation relative to said dogging member and the stationary portion when said rotatable spindle is in latch bolt withdrawn position, and a second position of adjustment wherein said rotatable spindle is unblocked relative to the dogging member and stationary portion.

2. In a door lock a frame, a first spindle bearing and a second spindle bearing comprising a stationary portion, a reciprocating latch bolt, a retractor reciprocatably mounted in the frame and operatively connected to the latch bolt, a first spindle having a. knob thereon and mounted in said first spindle bearing and a second spindle having a knob thereon and mounted in said second spindle bear, at least one of said spindles being a rotatable spindle in the respective bearing and having roll-back means thereon in operative engagement with the retractor, the combination of a clogging member having a nonroitatable engagement at all times with said stationary portion and having an operative association with said rotatable spindle in dilferent positions of adjustment, said dogging member having a first position of adjustment wherein said rotatable spindle is blocked against rota- 'tion relative to the stationary portion when said rotatable :spindle is in latch bolt withdrawn position, and a second position of adjustment wherein said rotatable spindle is unblocked relative to the stationary portion, a dog actuator in one of said spindles, an actuating connection be- .tween said actuator and said dogging member, said actuator enabling movement of said dogging member between said first and second positions, and a manually actuated hold back operating element in one of said spindles operatively connected to said dog actuator. 3. in a door lock 21 frame, a first spindle bearing and a second spindle bearing comprising a stationary portion, a reciprocating latch bolt, a retractor reciprocatably mounted in the frame and operatively connected to the latch bolt, a first spindle having a knob thereon and mounted in said first spindle bearing and a second spindle having a knob thereon and mounted in said second spindle bearing, said spindles being rotatable in said bearings and having roll-back means thereon in operative engagement with the retractor, the combination of a first dogging member in nonrotatable engagement with the stationary portion and having an operative association with one of said spindles in different positions of adjustment, said dogging member having a first position of adjustment wherein said one spindle is blocked against rotation relative to the stationary portion when said one spindle is in latch bolt withdrawn position, and a second position of adjustment wherein said one spindle is unblocked relative to the stationary portion, a dog actuator in one of said spindles, an actuating connection between said actuator and said dogging member, said actuator enabling movement of said dogging member between said first and second positions, a manually actuated hold back operating element in one of said spindles operatively connected to said dog actuator, a second dogging member in nonrotatable engagement with the stationary portion and having an operative association with the other of said spindles in different positions of adjustment, said second dogging member having a first position of adjustment blocking rotation of said other spindle and a second position of adjustment wherein said other spindle is unblocked, and a hold back connection between said dogging members responsive to operation by said first dogging member whereby both said spindles are blocked against rotation when said latch bolt is held in said withdrawn position.

4. In a door lock a frame, an outer spindle bearing and an inner spindle bearing comprising a stationary portion, a reciprocating latch bolt, a retractor reciprocatably mounted in the frame and operatively connected to the latch bolt, an outer spindle having a knob thereon and mounted in the outer spindle bearing and an inner spindle having a knob thereon and mounted in the inner spindle bearing, said spindles having roll backs respectively in operative engagement with the retractor, the combination of an outer dogging member having -a nonrotatable engagement with the stationary portion and means on the stationary portion having a releasable engagement with said dogging member when the outer spindle is in latch bolt extended position, an axially shiftable inner dogging member having a non-rotatable position relative to the stationary portion and having one axial position wherein said inner spindle is non-rotatable relative to the inner dogging member when the inner spindle is in latch bolt withdrawn position and another axial position wherein said inner spindle is rotatable relative thereto, a hold-back rod extending between said outer dogging member and said inner dogging member, a spring bearing against said inner dogging member, a hold-back operator in engagement with said hold-back rod, a first cam on said hold back operator, a second cam in camming engagement with said first cam, and an inner hold-back device in operating engagement with one of said cams whereby when said latch bolt is in retracted position said dogging extensions are movable by said hold-back device into positions barring rotation of said spindles.

5. In a door lock a frame, an outer spindle bearing and an inner spindle bearing comprising a stationary portion, a reciprocating latch bolt, a retractor reciprocatably mounted in the frame and operatively connected to the latch bolt, an outer spindle having a knob thereon and mounted in the outer spindle bearing and an inner spindle having a knob thereon and mounted in the inner spindle bearing, said spindles having roll backs respectively in operative engagement with the retractor, the combination of an outer dogging member and means on the stationary portion having a nonrotatable engagement with said dogging member in all positions of the outer spindle, an inner dogging member having a non-rotatable position relative to the stationary portion in all positions of the inner spindle, a hold-back rod, a hold-back operator in engagement with said hold-back rod, a first cam on said hold-back operator, a second cam in camming engagement with said first cam, and an inner hold-back device in operating engagement with said second cam whereby when said latch bolt is in retracted position said dogging members are movable by said hold-back device into positions barring rotation of said spindles and whereby when said inner spindle is in latch bolt released position said outer dogging member is movable by said inner hold-back device to a position barring rotation of said outer spindle and said inner spindle remains in operative engagement with said latch bolt.

6. In a door lock a frame, an outer spindle bearing and an inner spindle bearing comprising a stationary portion, a reciprocating latch bolt, a retractor reciprocatably mounted in the frame and operatively connected to the latch bolt, an outer spindle having a knob thereon and mounted in the outer spindle bearing and an inner spindle having a knob thereon and mounted in the inner spindle bearing, said spindles having roll backs respectively in operative engagement with the retractor, the combination of an axially movable outer dogging member having an inwardly spring pressed axially reciprocatable and nonrotatable mounting in the outer spindle, a dogging extension on the dogging member and means on the stationary portion having a nonrotatable engagement with said extension in all positions of the outer spindle, an axially movable inner dogging member having a non-rotatable and axially reciprocatable mounting in the stationary portion and having one axial position wherein said inner spindle is nonrotatable relative thereto when the inner spindle is in latch bolt withdrawn position and another axial position wherein said inner spindle is rotatable relative thereto, a hold-back rod extending between said outer dogging member and said inner dogging member, a holdback operator in axial engagement with said rod, means extensions are movable in response to movement of said hold-back device into positions barring rotation of said spindles when said latch bolt is held in retracted position by said inner spindle.

References Cited in the file of this patent UNITED STATES PATENTS 720,986 Voight Feb. 17, 1903 2,279,591 Heyer Apr. 14, 1942 2,838,926 Schmid June 17, 1958 

